Process of preparing duplicating-stencils.



UNITED STATES PATENT OFFICE.

LOUIS E. rULnnn,,'-0r' NEW YORK, 1v. 1, A-SSIGJSTOR, BY MEs'nE ASSIGNMENTS, TO

A 13. men commas, or CHICAGO, ILLmoI's', A

CORPORATION OF ILLINOIS.

PROCESS OF PREPARING DlJPLICATING-STENCILS.

1 101 ,2'70. No Drawing.

Specification of Letters Patent.

Application filed August 9, 1911.

Patented June 23, 1914. Serial No. 643,149.

To all wh'om it may concern Be it known that I, LOUIS E. FULLER, a citizen of the United States, and a resident of the city of New York, county and State of New York, have invented certain new and useful Improvements in Processes of Preparing Duplicating-Stencils, of which the following is a; specification.

This invention relates to processes of printing multiple copies by means of a suit-- able stencil.

The invention is directed to the-provision of a process of preparing duplicating stencils'wh-i-ch is more convenient and economical touse and with which better results are obtained, the improved process being particu'l'arly' advantageous in that the stencisheets employed are not afi'ected by temperatime changes and will produce a greater number and clearer copies. than stencilsheets of the character heretofore commonly employed.

The stencil sheets now in general use are made by coating a porous fibrous sheet, such as Japanese Ycshino paper with a coating of a parafiin composition impervious tomk. To make a stencil, the sheet so prepared is placed in a typewriter and the latter is operated in the usual manner; the blow of the type causes removal of the waxy coating along lines struck by the type, leaving the porous base exposed along those lines. Also, the stencil may be similarly prepared by writing upon the sheet with a suitable stylus. The process of duplicating involving the use of such a stencil has not proven entirely satisfactory because, with stencils so prepared, the number of copies that can be made is limited, the copies are not as clear as is desired and the stencil sheets deteriorate with changes of temperature.

In accordance with this invention, the, stencils are prepared by a radically diiferent method whereby far superior results are obtained. Stencil-sheets are employed having a dry, insoluble, hygroscopic coating of a colloidal character which is impervious to ink; such a sheet is mo-istenedwhen 1t 1s desired to prepare a stencil; while in a moisi tened' condition, the sheet is: impressed with the characters to be reproduced; thereafter the sheet is dried. Such a dry, insoluble sheet will not be affected by temperature changes so that it will always be in a condition for use though kept for a. considerable length of time. When it is desired to prepare a stencil, the surface of the sheet is moistened, and, because of the hygroscopic character of the coating, a limited amount of moisture is taken up by the coating, as a result of which the coating expands and assumes a cellular structure. Then on impress mg the sheet with the characters to be reproduced, the cellular formation of the coatin-g is broken down along the lines of the chardried and in drying the material of the coatmg shrinks so as to enlarge the spaces along the lines of impression and the stencil is ready for use. The coating for the fibrous sheets which I have found most suitable is a, coating consisting of a coagulated protem. Thus gelatin may be employed coagulated by a chromic agent such as potassium dichromate. 'VVith this is preferably employed a tempering agent, such as glycerin or sugar or a mixture of the two.

The sheets for use in practising the process may be prepared as follows: First, a concent-rated solution of gelatin, sugar, acetic acid and water is prepared. The proportions of these ingredients may be reasonably varied, with the result that the compound will be thicker or thinner. The solution which I have found to be the best and most useful is as follows: gelatin, one part; white sugar, one part; glacial acetic acid pure, one part; glycerin, two parts; water, two parts, all by weight; potassium dichromate in crystals enough to color the compound a deep yellow.

7 The gelatin should first be broken into pieces of a convenient size and dissolved in the acetic acid and water, a gentle heat, such as a water bath, being applied, if it be desirable to effect solution in a shorter period of time. The sugar and glycerin are then add-' the ingredients are completely blended and dissolved. The potassium dichromate, preferably powdered crystals, is then added to l-th'e extent of as much as the solution will dissolve, or at least enough to color the compound a deep yellow. The whole is then filtered b suitable means.

| The so ution may be applied to the paper 5 by laying the sheet on asmooth non-absorpt-ive surface, as a plate of glass, and flowing the solution thereover by means of a brush, 1 a dim light being desirable in this operation acter impressions. Thereafter, the sheet is 1 edand the whole thoroughly mixed, so that as in the operation of preparingthe solution. The sheet is then suspended to dry, and when dried it is exposed to daylight or other suitable light. l/Vithin a shorterv or longer time, dependent upon the intensity of the light, the sheet will change in color to a grayish green or lavender, such change being due to the reduction of potassium dichromate to chrome alum and coagulation of the gelatin. By such exposure and reduction, the compound is rendered insoluble in water, hot or cold, except that it will soften slightly under the influence of moisture and is ygroscopic. It is also rendered proof againstall neutral solvents and against concentrated alkaline and dilute acid solutions. It is also proof against oils and greases, and all solvents of the same. The sheets so prepared can therefore be kept through a long .as concerns the present invention,

perlod of time and will not deteriorate under changes of temperature.

The foregoing is given as a method for preparing coated sheets which may be used in practising the improved process of duplicating, but I wish it understood that, so flar t is method may be varied considerably so long as the sheets produced are capable of use in accordance with my improved process.

When it is desired to prepare a stencil from a sheet so coated the first step is to moisten the surface of the sheet. This may be done in any suitable and convenient manner, as for instance, by passing a moistened sponge over the surface of the sheet. When the surface of the sheet is so moistened, the coating, by reason of its hygroscopic characteristic, takes up a limited amount of the moisture, expands, and assumes a cellular structure. After the sheet has been so moistened, it may be impressed with the characters which are to be reproduced. This may be done in any suitable manner, as for instance, by placing the sheet in an ordinary type-writing machine and operating the machine in the usual manner. When the type of the machine strikes the coated sheet, it breaks down the cellular structure of the coating along the lines of the characters to be reproduced. It is not necessary to cut out the coating, but merely to break down or crush the cellular structure. The same result may be accomplished by writing upon the sheet with a suitable stylus instead of impressing the sheet with type characters with a type-writing machine. Afterthis has been done, the sheet is dried. As the coating dries, it contracts and its edges about the character impressions drawback so as to enlarge the spaces along the lines of impression. The stencil is then ready for use in the usual manner. When placed in a frame and an ink-roller passed thereover, the ink will pass freely through the portions of the sheet which have been impressed and reproduce the characters upon an. underlying impression sheet. "Also such a stencil ma be used upon a rotary stencil-duplicatlng machine or in an addressing machine in the usual manner. In addition to the fact that the stencils prepared in accordance with this invention are free from deterioration under changes of temperature, stencils so prepared are stronger than the stencils heretofore commonly used provided with a waxy coating. Also, the coating will not crack when the sheet is bent, as frequently occurs with wax-coated sheets, so that the danger of spoiling a sheet in the process of preparation of the stencil is greatly reduced. Furthermore, a stencil prepared in accordance with the invention may be used in producing a very large number of copies, a number greatly in excess 'of the number which can be produced with'a stencil-sheet having a waxy coating. These copies, moreover, will be greatly superior in clearness and uniformity of the printed characters to those produced ;by' the processes heretofore commonly emplo e I v 1 1 Having described my invention, what I claim as newtherein and desire to secure by Letters Patent of the United States is:

1. The process of preparing stencils which consists in impregnating a porous fibrous sheet with acolloidal'substance, rendering such sheet normally dry but hygroscopic, -temporarily moistening'said sheet, impressing characters therein and then drying said sheet, substantially asset forth.

2. The process of preparing stencils which consists in impregnating a porous fibrous sheet with a colloidal substance and a tempering agent, rendering such sheet normally dry but hygroscopic, temporarilymoistening said sheet, impressing characters therein and then drying said sheet, substantially as set forth. f

3. The process of preparing stencils which consists in impregnating a porous fibrous sheet with a colloidal substance, rendering a such sheet normally dry but hygroscopic, temporarily softening said sheet, @impressing characters therein and then drying said sheet, substantially .as set forth. 1

1 4. Theprocess of preparing stencils which 5 consists 1n impregnating .a porous fibrous sheet with acolloidal substance and a tempering agent, rendering-such sheet normally dry but hygroscopic, temporarily softening said sheet, impressing characters therein and I ing an insoluble, hygroscopic coating to aporous fibrous sheet, moistening the stencilsheet so made as an incident to cutting the stencil and to prepare the sheet for the cutting of the stencil, impressing the sheet with the characters to be reproduced while the sheet is in the moistened condition, and then drying the sheet, substantially as set forth.

6. The process of preparing stencils which consists in applying to a porous fibrous sheet a coating of a coagulated protein, moistening the sheet, impressing the sheet with the characters to be reproduced while the sheet is in the moistened condition, and then drying the sheet, substantially as set forth.

7. The process of preparing stencils which consists in applying to a porous fibrous sheet a coating of coagulated protein, moistening the sheet, impressing the sheet with the characters to be reproduced while the sheet is in the moistened condition, then drying the sheet, substantially as set forth.

8. The process of preparing stencils which consists in applying to a porous fibrous sheet a hygroscopic coating of a coagulated protein, moistening the sheet, impressing the sheet with the characters to be reproduced, while the sheet is in the moistened condition, and then drying the sheet, substantially as set forth.

9. The process of preparing stencils which consists in applying to a porous fibrous sheet, a hygroscopic coating of a coagulated protein and a tempering agent, moistening the sheet, impressing the sheet with the characters to be reproduced while the sheet is in the moistened condition, and then drying the sheet, substantially as set forth.

10. The process of preparing stencils which consists in applying -to a porous fibrous sheet a hygroscopic coating consisting of a protein coagulated by a chromic coagulating agent, moistening the sheet, im pressing the sheet with the characters to be reproduced while the sheet is in a moistened condition, and drying the sheet, substantially as set forth.

11. The process of preparing vstencils which consists in applying to a fibrous sheet a hygroscopic coating impervious to ink, moistening the sheet and thus causing the coating to expand, impressing the sheet with the characters to be reproduced while the coating is so expanded, and then drying the sheet, substantially as set forth.

12. The process of preparing stencils I which consists in applying to a fibrous sheet a hygroscopic coating of a coagulated protein, moistening the sheet andthus causing the coating to expand and assume a cellular structure, impressing the sheet while so moistened with characters to be reproduced and thus breaking down the cellular structure along the lines of the characters, and then drying the sheet, substantially as set forth.

13. The process of preparing stencils which consists in applying to a porous fibrous sheet an insoluble, hygroscopic coat ing impervious to ink, moistening the sheet, impressing the sheet with the characters to be reproduced while the sheet is in the moistened condition, and then drying the sheet and shrinking the material so as to enlarge the spaces along the lines of impression, substantially as set forth.

14c. The process of preparing stencils which consists in applying to a porous fibrous sheet a hygroscopic'coating of a coagulated protein, moistening the sheet, impressing the sheet with the characters to be reproduced while the sheet is in the moistened condition, and then drying the sheet and shrinking the material along the lines of type impressions, substantially as set forth. a

15. The process of forming a stencil which consists in appling to a fibrous sheet a composition of proteincombined with a chromic coagulating agent, exposing the sheet to light to produce coagulation, softening said protein, impressing characters therein while the same is in softened condition and then drying said sheet and the material carried thereby, substantially as described.

16. The process of forming a stencil which consists in applying to a fibrous sheet a composition having predetermined hygroscopic properties, temporarily softening said composition by the application of moisture and while in a softened condition severing the surface thereof according to the conformation of a character or characters to be reproduced and then drying said sheet, substantially as set forth.

This specification signed and witnessed this 3rd day of August, 1911.

LOUIS E. FULLER.

Witnesses:

S. O. 'EDMONDS, I. MoIN'rosH.

Corrections in Letters Patent No. 1,101 ,270.

Disclaimerin LetterPatentsN0.'1,101 ,270.

It ishereby certified that in Letters Patent No. 1,101,270, granted June 23, 1914, upon the application of Louis E. Fuller, of New York, N. Y., for an improvement in Processes of Preparing Duplicating-Stencils, errors appear in the printed specification requiring correction-as follows: Page 3, line 59, before the word characters insert the article the; same page, line 82, for the Word impressions read impres sz'on; and line 85, for the vvord appling read applying; and that the said Letters Patent should be read with these correctionstherein that the same may conform to the record of the case in the Patent Ofiice.

Signed and sealed this 14th day of July, D., 1914.-

' J. T. NEWTON,

Acting Commissioner of Patents.

[snub] DISCLAIMER- 1,101,270.Lowis E. Fuller, New York,.N. Y. PRoo ss 0F PREPARING DUPLI- CA'IING-STENCILS. Patent dated June 23, 1914. Disclaimer filed December 4, 1916, "by the assignee, A. B. Dick Company. Enters its disclaimer as follows, to wit: 1. It disclaims, under said LettersPatent, any and all process or processes which include impregnating a fibrous sheet, except such as involve impregnating Japanese Yoshino paper or its equivalent. I

2. It disclaims, under said Letters Patent, any and all process or processes of preparing or forming stencils which does not or do not involve forming the characters by impact or pressure, such, for example, as the action of the type of a writingmachine;

[Oflicial Gazette, December 12, 1.916.] 

